Earlier this year, a 7-year-old girl from Minnesota entered an examination room at a clinic just outside of Detroit. Thinking this was a regular visit, she allowed the doctor to remove her pants and underwear and place her on the examination table. Suddenly, while two women in the clinic held her hands, the physician spread her legs and cut her clitoris. Two months later she told investigators the pain ran down to her ankles and she could barely walk.

In April Dr. Jumana Nagarwala, who allegedly performed the procedure, was charged with conspiracy to commit female genital mutilation. Dr. Fakhruddin Attar, the owner of the since-closed clinic, was also charged.

Investigators suspect Ms. Nagarwala may be involved in 100 other cases, and the trial starts in October. This marks the first time a female genital mutilation case is going to federal court. The lawyers for the Michigan physician will argue the girl “underwent a benign religious procedure.” This is a dangerous hypocrisy with far-reaching consequences.

Female genital mutilation has been illegal in the U.S. since 1996. Yet a 2012 study in the journal Public Health Reports estimates that more than 500,000 girls in the U.S. have undergone the procedure or are at risk.

These girls live all over the country, with larger Muslim concentrations in California, New York and Minnesota. Most go through this process in secret, and only 25 states have laws that criminalize the procedure. In Maine, the American Civil Liberties Union has opposed a bill to do so on the ground that “the risk of mutilation isn’t worth expanding Maine’s criminal code.”

Female genital mutilation, most often performed on girls under 13, has serious medical and psychological repercussions. The cutting ranges from a clitoridectomy, partial to total removal of the clitoris, to infibulation, removal of all the external genitalia. The latter is so severe that “healing” often involves binding the girl from ankle to waist until the scar tissue closes. This kind of cutting leaves an opening the width of a pencil for urination, menstruation, sex and childbirth.

In 2015 a U.N. official estimated that 20% of parents take their daughters to physicians but the rest use improvised sharp objects.

This spring, an Ethiopian man in Georgia was deported for performing female genital mutilation with a pair of scissors on his 2-year-old daughter. Parents fearing prosecution sometimes take their girls out of the country for “vacation cutting.”

A report from Unicef suggests at least 200 million girls and women alive today, in 30 countries, have undergone some form of it. (The U.S. Commission on International Religious Freedom, of which I am vice chairwoman, does not take an official position on female genital mutilation.)

Whether this practice is religious or cultural is debatable. In the Michigan case, the victims belong to an Indian Shiite Muslim sect called the Dawoodi Bohra, whose members refer to the clitoris as a sinful lump of flesh.

The cutting, khatna, is considered a religious observance to prevent girls from becoming promiscuous. Yet female genital mutilation predates Christianity and Islam. No religious text requires it. Many imams have issued fatwas against the practice and Christian leaders like Pope Francis have denounced it.

The physician’s lawyers announced they will craft a religious-freedom defense. And they may be astute enough to get away with it. The all-star team includes constitutional law scholar and O.J. Simpson lawyer Alan Dershowitz, along with Mayer Morganroth, (Shame on them. I don’t think they will find this procedure within their own Hebrew bible – Not that that matters to them jsk ) who represented assisted-suicide champion Dr. Jack Kevorkian for more than 15 years. They are funded by an international Muslim organization called Dawat-e-Hadiyah.

The lawyers must know they are entering dangerous territory, at least in terms of public relations. After coming under criticism for defending female genital mutilation, Mr. Dershowitz suggested during a June interview that pricking the girls’ clitoris would be a better way to fulfill a “religious legal obligation.” This is absurd. There is no such obligation.

The physician’s lawyers have not only put these girls at even greater risk, they have tainted the religious freedom of all Americans with their specious arguments.

Religious freedom is a bedrock right that ensures all can live according to their convictions. It also allows for the existence of charities providing Americans with an equivalent of $1.2 trillion annually in food, shelter, medical care and more. It is not a tool to protect harmful practices like female genital mutilation.

These girls are among the most vulnerable in society. For their sake, Americans must raise their voices against this detestable practice. Doing what is right may also yield an important social good: the restoration of religious freedom to its proper place in American culture and jurisprudence.Ms. Arriaga is a contributor at the Pepperdine School of Public Policy.